Introduction: The benefit of intervention for patients with unruptured intracranial arteriovenous malformations (AVM) was challenged by results demonstrating superior clinical outcomes with conservative management from A Randomized Trial of Unruptured Brain AVMs (ARUBA). The aim of this multicenter, retrospective cohort study is to analyze the outcomes of stereotactic radiosurgery for ARUBA-eligible patients.

Methods: We combined AVM radiosurgery outcome data from seven institutions participating in the International Gamma Knife Research Foundation (IGKRF). Patients with =12 months of follow-up were screened for ARUBA eligibility criteria. Favorable outcome was defined as AVM obliteration, no post-radiosurgery hemorrhage, and no permanently symptomatic radiation-induced changes (RIC). Adverse neurological outcome was defined as any new or worsening neurological symptoms or death.

Results: The ARUBA-eligible cohort comprised 509 patients (mean age 40 years). The Spetzler-Martin grade was I-II in 46% and III-IV in 54%. The mean radiosurgical margin dose was 22 Gy and follow-up was 86 months. AVM obliteration was achieved in 75%. The post-radiosurgery hemorrhage rate during the latency period was 0.9%/year. Symptomatic and permanent RIC occurred in 11% and 3%, respectively. The rates of favorable outcome, adverse neurological outcome, permanent neurological morbidity, and mortality were 70%, 13%, 5%, and 4%, respectively.

Conclusions: Radiosurgery may provide durable clinical benefit in some ARUBA-eligible patients. Based on the natural history of untreated, unruptured AVMs in the medical arm of ARUBA, we estimate that a follow-up duration of 15-20 years is necessary to realize a potential benefit of radiosurgical intervention over conservative management in unruptured AVM patients.

Patient Care: The management of unruptured AVMs is a controversial topic. The initial results from A Randomized Trial of Unruptured Brain AVMs (ARUBA) showed significantly worse outcomes after intervention compared to conservative management for unruptured AVM patients. However, ARUBA was appropriately criticized for a number of weaknesses. In this retrospective, multicenter analysis, we attempt to address some of the shortcomings of ARUBA and show that, for appropriately selected ARUBA-eligible patients, treatment with radiosurgery may provide a long-term benefit over conservative management.

Learning Objectives: By the conclusion of this session, participants should be able to 1) Describe the importance of stereotactic radiosurgery in the management of ARUBA-eligible patients, 2) Discuss, in small groups the outcomes after radiosurgery in patients who were eligible for A Randomized Trial of Unruptured Brain AVMs (ARUBA), and 3) Identify an effective treatment for unruptured brain arteriovenous malformations.

References: 1. Ding D, Starke RM, Kano H, et al. Radiosurgery for Cerebral Arteriovenous Malformations in A Randomized Trial of Unruptured Brain Arteriovenous Malformations (ARUBA)-Eligible Patients: A Multicenter Study. Stroke. Feb 2016;47(2):342-349.